There are actually some good zucchini relish recipes out there. I can it in half pints and use it in place of pickle relish on hot dogs, in potato or egg salad.
Your post reminded me of a recipe I read about recently:
http://www.thekitchn.com/summer-recipe-pickled-yellow-squash-recipes-from-the-kitchn-175125
She sorta makes me want to taste the actual original recipe that she’s writing about; but the chef’s ‘lips were sealed’ :-)
-JT